The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 16, 1994
Filed:
Jul. 07, 1993
Hiroshi Matsuoka, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In a method for producing a recessed gate field effect transistor including a recess in a semiconductor substrate and a gate electrode disposed in the recess, a photoresist film is applied to the semiconductor substrate and source and drain electrodes on the substrate, a first insulating film is formed on the photoresist film, a resist pattern, which has an opening for processing the first insulating film and the photoresist film are etched using the resist pattern as a mask to form an opening having a width increasing in the direction of the substrate, a second insulating film is formed on opposite side walls of the opening, the semiconductor substrate is etched using the opening narrowed by the second insulating film in the substrate to form a recess, the second insulating film is selectively removed by etching, gate metal is deposited on the photoresist and on the substrate in the recess, and unnecessary gate metal is removed by lifting-off the resist film.